The sound emanating from a brass musical instrument is affected by numerous physical parameters. As is well-known, such sound is much more than just the frequency of the fundamental note being played by the musician but also includes the resonances of the various parts of the instrument, all of which provide the “color” to the sound being produced by the musical instrument.
A brass instrument produces a musical note when the air column in the instrument is excited into resonance by the musician introducing air into the windpath through a mouthpiece. The process of sound formation is extremely complex and even includes the musculature of the musician and the instant muscle tone thereof. Among the physical parameters of the instrument which are important are the windpath tubing material and material thicknesses, the shape of the windpath, and the location and type of bracing used. Thus, bracing is an important element in the determination of the character of the resulting sound.
Musicians often characterize an instrument as having a certain “feel,” and the feel of the instrument is affected by the resonances of the instrument. Changing the feel involves changing anything which affects the resonances of the instrument. Musicians would like to be able to change the feel and sound of an instrument depending on the type of music being played without the expense of having multiple instruments with different materials, shapes, bracing, etc. For example, early-period music requires a lighter, more transparent sound than more contemporary music, and thus there is a need for brass instruments which can produce many different types of sound simply by carrying out an adjustment of the instrument.
In the construction of brass musical instruments, the use of bracing is required for structural integrity while limiting the number of braces helps to keep stresses out of the instrument and also reduces manufacturing cost.